Nearly Isotropic Upper Critical Field in Pressurized Trilayer Nickelate La4Ni3O10−δ

Abstract

Evidence of superconductivity has recently been reported in pressurized nickelates, providing a new platform to explore high-temperature superconductivity. However, detailed experimental characterization of the superconducting properties of nickelates under pressure remains limited and technically challenging. Here, we report the first full temperature-dependent measurements of the upper critical field (μ0Hc2) in pressurized trilayer nickelate La4Ni3O10−δ single crystal, achieved by integrating advanced high-magnetic-field and high-pressure techniques. Remarkably, La4Ni3O10−δ exhibits nearly isotropic superconductivity, with the anisotropic parameter γ decreasing monotonically from 1.4 near Tc to 1 at lower temperatures. By applying a two-band model analysis out of plane and in plane μ0Hc2, we uncover a compensation of anisotropic diffusivity between bands primarily originating from dz2 and dx2−y2 orbitals, resulting in an exceptionally isotropic superconducting characteristic. These findings indicate the significant contribution of the dz2 orbital to superconductivity in pressurized La4Ni3O10−δ and provide essential constraints for theoretical models of the pairing mechanism in Ruddlesden-Popper nickelates.

Source-reported materials — not catalogue approval

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